During low speed operation of a permanent magnet (PM) electric motor in accordance with conventional algorithms that estimate the rotor position based on the voltage and current without using the rotor position or speed sensor (i.e., in accordance with “sensorless algorithms”), a high frequency signal is injected into a flux axis of a motor stator winding of the PM electric motor and the torque axis of the motor stator winding is monitored to derive rotor position and speed information without using any mechanical position or speed sensor. While this sensorless method works well for internal PM motors which are designed not to saturate under full load conditions, presently PM motors are required to have the highest possible power density. Such PM motors would necessarily be able to operate in heavy saturation at high load conditions.
Accordingly, it is desirable to provide a method and apparatus for sensorless operation of a permanent magnet motor which provides robust low speed control under heavily saturated operating conditions. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.